From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751722AbdBUJoP (ORCPT ); Tue, 21 Feb 2017 04:44:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:47583 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751467AbdBUJoA (ORCPT ); Tue, 21 Feb 2017 04:44:00 -0500 Date: Tue, 21 Feb 2017 10:43:54 +0100 From: Michal Hocko To: Shaohua Li Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kernel-team@fb.com, danielmicay@gmail.com, minchan@kernel.org, hughd@google.com, hannes@cmpxchg.org, riel@redhat.com, mgorman@techsingularity.net, akpm@linux-foundation.org Subject: Re: [PATCH V2 5/7] mm: add vmstat account for MADV_FREE pages Message-ID: <20170221094353.GG15595@dhcp22.suse.cz> References: <20170210132727.GM10893@dhcp22.suse.cz> <20170210175015.GD86050@shli-mbp.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170210175015.GD86050@shli-mbp.local> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Sorry for a late reply I was on vacation last week] On Fri 10-02-17 09:50:15, Shaohua Li wrote: > On Fri, Feb 10, 2017 at 02:27:27PM +0100, Michal Hocko wrote: > > On Fri 03-02-17 15:33:21, Shaohua Li wrote: > > > Show MADV_FREE pages info in proc/sysfs files. > > > > How are we going to use this information? Why it isn't sufficient to > > watch for lazyfree events? I mean this adds quite some code and it is > > not clear (at least from the changelog) we we need this information. > > It's just like any other meminfo we added to let user know what happens in the > system. Users can use the info for monitoring/diagnosing. the > lazyfree/lazyfreed events can't reflect the lazyfree page info because > 'lazyfree - lazyfreed' doesn't equal current lazyfree pages and the events > aren't per-node. I'll add more description in the changelog. Well, I would prefer to not add new counters until there is a strong reason for them. Maybe a trace point would be more appropriate for debugging purposes. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 498A76B0389 for ; Tue, 21 Feb 2017 04:44:00 -0500 (EST) Received: by mail-wm0-f69.google.com with SMTP id t18so14685225wmt.7 for ; Tue, 21 Feb 2017 01:44:00 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id k19si15742528wmi.125.2017.02.21.01.43.58 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 21 Feb 2017 01:43:58 -0800 (PST) Date: Tue, 21 Feb 2017 10:43:54 +0100 From: Michal Hocko Subject: Re: [PATCH V2 5/7] mm: add vmstat account for MADV_FREE pages Message-ID: <20170221094353.GG15595@dhcp22.suse.cz> References: <20170210132727.GM10893@dhcp22.suse.cz> <20170210175015.GD86050@shli-mbp.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170210175015.GD86050@shli-mbp.local> Sender: owner-linux-mm@kvack.org List-ID: To: Shaohua Li Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kernel-team@fb.com, danielmicay@gmail.com, minchan@kernel.org, hughd@google.com, hannes@cmpxchg.org, riel@redhat.com, mgorman@techsingularity.net, akpm@linux-foundation.org [Sorry for a late reply I was on vacation last week] On Fri 10-02-17 09:50:15, Shaohua Li wrote: > On Fri, Feb 10, 2017 at 02:27:27PM +0100, Michal Hocko wrote: > > On Fri 03-02-17 15:33:21, Shaohua Li wrote: > > > Show MADV_FREE pages info in proc/sysfs files. > > > > How are we going to use this information? Why it isn't sufficient to > > watch for lazyfree events? I mean this adds quite some code and it is > > not clear (at least from the changelog) we we need this information. > > It's just like any other meminfo we added to let user know what happens in the > system. Users can use the info for monitoring/diagnosing. the > lazyfree/lazyfreed events can't reflect the lazyfree page info because > 'lazyfree - lazyfreed' doesn't equal current lazyfree pages and the events > aren't per-node. I'll add more description in the changelog. Well, I would prefer to not add new counters until there is a strong reason for them. Maybe a trace point would be more appropriate for debugging purposes. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org